The present subject matter relates generally to a system for remote unit-dose monitoring of prescription medicine. More specifically, the present invention relates to remote unit-dose monitoring of a blister packaging for medicaments.
Monitoring devices have become increasingly common for remote inventory control and remote status-awareness of products with characteristics such as high commercial value or safety concerns. Any prescribed medication classified as a Controlled Substance is an example of a product with both high street value and safety concerns. Examples of sensing devices for monitoring prescription medications are found in these publications, the entirety of each is incorporated by reference: U.S. Patent Application Publication No. 2013/0285681 A1, U.S. Pat. No. 7,178,417, U.S. Pat. No. 7,113,101, and U.S. Pat. No. 6,244,462. In order to enjoy broad utilization in high-volume applications such as routine medical care, monitoring devices must have very low complexity and costs.
The high street value and the highly addictive nature of Controlled Substances merit the use of unit-dose monitoring of each and every dose rather than the collection of less-informative data such as bottle open-and-close cycles. Unit-dose monitoring requires each dosage unit (i.e., each pharmaceutical pill, capsule, tablet, etc.) to be packaged individually with a means to remotely monitor for the presence or absence of each dose. Unit-dose monitoring may be accomplished with blister packaging, such as those described in the publications listed above that combine a blister shell with a means to monitor the removal of individual doses. Blister shells are product receptacles or product cavities within which individual doses are placed. In monitoring devices commercialized to date, the individual circuit paths are aligned with or affixed to medication blisters so that they correspond to a single blister or product receptacle, and the action of pressing against the product receptacle causes the product to pierce engineered failure points (weakened by, for example, die cutting) causing the disruption of the single corresponding circuit path.
In part because of limitations of circuitry approaches used to date, the applications of pharmaceutical unit-dose monitoring have not found widespread commercial use, but instead have been limited to serving small markets such as the monitoring of medications in clinical trial investigations sponsored by pharmaceutical companies. As a single example only, FIG. 13 of U.S. Patent Application Publication No. 2013/0285681 A1 shows the following limitations caused by the simple approaches in use to date: A) the complexity and number of conductive leads required to monitor just twelve doses shows that this approach would lead to very large packaging dimensions if expanded to monitor normally dispensed numbers of doses such as a one-month supply, for example; B) the complexity of the connection between the sensing leads and the monitoring electronics becomes very complex even when only moderate numbers of doses are monitored. For the purpose of this document, the simple circuitry approaches commercialized to date are termed “trace loops” because the monitoring of a single product receptacle requires a conductive loop that is dedicated to the receptacle plus a shared return conductor. In the example shown at FIG. 13 of U.S. Patent Application Publication No. 2013/0285681 A1, the monitoring of ten doses requires twelve dedicated leads combined with one shared conductor, so the connector must accommodate a total of thirteen conductive leads. As a further burden on the patient, FIG. 13 of U.S. Patent Application Publication No. 2013/0285681 A1 shows that the size of the packaging is dictated by the number of trace loops rather than by the size of the product being monitored. Product density, the number of products being monitored per unit of surface area, decreases rapidly with the trace-loop approach when clinically meaningful numbers of dosage units are monitored. Trace-loop circuitry approaches have been commercialized in the clinical-trials market to date because, contrary to routine medical care, people are typically paid to participate and are tightly monitored by the trial sponsor, so cumbersome packaging solutions are tolerated. These and other long-established shortcomings of commercialized approaches have been outlined in U.S. Pat. No. 7,178,417 (Column 1, Line 63 through Column 2, Line 7). Thus, because in-pharmacy assembly of smart packaging necessitates simple, robust, easy to use, and inexpensive connectors and because patients will not tolerate oversize packaging, a trace-loop approach cannot scale to monitor clinically meaningful quantities of doses.
New and high-volume applications for medication monitoring will tolerate neither excessive packaging dimensions nor connector expense and complexity associated with current sensing approaches. For example, drug-safety packaging is being tested to determine whether objective data collected from the packaging may be used to slow the crisis of prescription drug abuse, trafficking, and attendant beneficiary fraud (www.divert-x.com). Because patients using this system are not paid (as in clinical trials) and are not monitored via vigorous, ongoing person-to-person interaction (as in clinical trials), large devices that are expensive and difficult to assemble would not be accepted in the marketplace. As a further complication, the Divert-X and competing hardware rely on monitoring electronics and product packaging that are combined through a connector to form the completed smart packaging. In the case of Divert-X, the packaging is assembled in retail pharmacies; given the time constraints of this environment, the connector must be simple, robust, easy to use, and inexpensive.
In order to attempt to resolve some of these issues, Petersen, et al. revealed a conductive grid sensing approach in U.S. Pat. No. 7,113,101 (the '101 patent). This art proposes a fine mesh-like, electrically-conductive grid that is used to cover the blister openings and the medication. The grid is made of sets of electrically-conductive leads originating on the X- and Y-axes that intersect at right angles, analogous to the appearance of graph paper. The spacing between individual leads and intersections is considerably smaller than between leads in commercially manufactured sensing products such that each product cavity will overlay several leads and intersections. Because several leads will intersect each blister opening in the '101 patent, each dose-removal event will be sensed by the permanent disruption of several intersecting leads. The working theory of the '101 patent is that the removal of a plurality of doses may be sensed and accounted for by monitoring “a change in the resistance of the circuit.”
The working theory of the '101 patent cannot be placed into practice for smart-blister packaging and, hence, this approach has not been commercialized. Specifically, the conductive grid design of the '101 patent cannot meet the aims of a compact, commercially-acceptable sensing packaging because of a technical problem we call “blinding.” Blinding is the loss of inventory or status data obtainable from the packaging. Blinding occurs because the sensing conductive grid is permanently changed by physical removal of conductive grid material resulting from dose removal from the packaging. Specifically, the action of pressing against the product receptacle causes the dose to pierce failure points engineered into the conductive grid, allowing the removal of the dose from the packaging. Consider a conductive grid such as that taught in the '101 patent affixed to a blister package for the purpose of monitoring an inventory of 25 medication doses arranged in a square of 5 rows and 5 columns. Removal of a dose at each end of a single row blinds the monitoring device for all doses on the same row. As additional doses are removed, the device becomes blinded to the point where no system may sense additional dosing events and no accurate inventory reporting is possible.
Accordingly, there is a need for a system of remote unit-dose monitoring that overcomes the problems of circuit crowding, low product density, blinding, and excessively complex and expensive connectors, as described herein.